Anne Frank's diary is a personal journal written by a Jewish girl named Anne Frank during World War II. She began writing it in 1942 while hiding with her family in Amsterdam to escape the Nazi persecution of Jews. The diary captures her thoughts, feelings, and experiences during this difficult time. The diary was discovered after the war and published as "The Diary of a Young Girl." It has since become one of the most important works of literature, providing insight into the life of a young girl facing the horrors of the Holocaust and the impact of war on humanity.